Emile Tan

Imperial College London, Londinium, England, United Kingdom

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Publications (28)180.42 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: AimThe efficacy of sacral nerve stimulation (SNS) in low anterior resection syndrome (LARS) is largely undocumented. A review of the literature was carried out to study this question.Method Pubmed, Medline and Cochrane databases were searched for relevant articles up to August 2014. Studies were included if they evaluated the use of SNS following rectal resection and assessed at least one of the following end points: bowel function, quality of life and ano-neorectal physiology. No restrictions on language or study size were made.ResultsSeven papers were identified including one case report and six prospective case series. These included 43 patients with a median follow-up of 15 months. After peripheral nerve evaluation (PNE) definitive implantation was carried out in 34 (79.1%) patients. Overall, 32 (94.1%) of the 34 patients experienced improvement of symptoms which, based on intention to treat, was 32/43 (74.4%).Conclusion The review suggests that SNS for faecal incontinence in LARS has success rates comparable to its use for other forms of faecal incontinence.This article is protected by copyright. All rights reserved.
    Colorectal Disease 04/2015; DOI:10.1111/codi.12968 · 2.02 Impact Factor
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    ABSTRACT: AimSeveral studies have suggested an increased lymph node yield, reduced loco-regional recurrence and increased disease-free survival (DFS) after complete mesocolic excision (CME) for colorectal cancer. This review was undertaken to assess the use of CME for colon cancer by evaluating the technique and its clinical outcome.MethodA literature search of publications was performed using Pubmed and Medline. Only studies published in English were included. Studies assessed for quality and data were extracted by two independent reviewers. Endpoints included numbers of lymph nodes per patient, quality of the plane of mesocolic excision, postoperative mortality and morbidity, 5 year locoregional recurrence and 5-year cancer-specific survival.ResultsThere were 34 articles comprising 12 retrospective studies, nine prospective studies, 13 original articles including case series, observational studies and editorials. Of the prospective studies, four reported an increased lymph node harvest and a survival benefit. The others reported an improvement in the quality of the specimen as assessed by histopathological examination. Laparoscopic CME has the same oncological outcome when compared with open surgery but completeness of excision during laparoscopy may be compromised for tumours in the transverse colon.Conclusion Studies demonstrate that CME removes significantly more tissue around the tumour including maximal lymph node clearance. There is little information on serious adverse events after CME and a long-term survival benefit has not been proven.This article is protected by copyright. All rights reserved.
    Colorectal Disease 10/2014; 17(1). DOI:10.1111/codi.12793 · 2.02 Impact Factor
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    ABSTRACT: AimLaparoscopic ventral rectopexy (VR) with the use of prosthesis has been advocated for both overt rectal prolapse (ORP) and obstructed defaecation syndrome (ODS). The present study reviews the short-term and functional results of laparoscopic VR.MethodA MEDLINE, Embase, Ovid, and Cochrane database search was performed on all studies reporting on VR for ORP, ODS and other pelvic floor anatomical abnormalities from 2004 until February 2013. No language restrictions were made. All studies on VR were reviewed systematically. The main outcomes were intraoperative complications, conversion, procedure duration, short-term mortality and morbidity, length of stay, ORP recurrence, anatomical disorder recurrence, faecal incontinence and constipation, quality of life (QoL) score and patient satisfaction. Quality assessment and data extraction were performed independently by three observers.ResultsTwenty three studies including 1,460 patients were eligible for analysis. The conversion rate ranged from 0 to 14.3%. No mortality was reported. The immediate postoperative morbidity rate was 8.6%. Length of stay ranged from 1 to 7 days. A significant improvement in constipation and incontinence symptoms was observed in the postoperative period for both ORP and ODS (chi-square test, p<0.0001).Conclusion Laparoscopic VR is a safe and effective procedure for ORP and ODS. Longer follow-up is required and studies comparing VR to standard rectopexy and STARR are not yet available.This article is protected by copyright. All rights reserved.
    Colorectal Disease 09/2014; DOI:10.1111/codi.12751 · 2.02 Impact Factor
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    ABSTRACT: AimA tension-free well vascularised colorectal or colo-anal anastomosis is not always possible following rectal or sigmoid resection. The study reports on the short-term and long-term outcome of a modified right colon inversion technique as a means of facilitating a low colorectal or anal anastomosis.Method All patients who underwent right colonic inversion, a modified Deloyer's procedure, were identified retrospectively from the prospective database of the Colorectal Department of the Royal Marsden Hospital from October 2008 to December 2013.ResultsThere were fourteen (9 male) patients of median age 58.7 (45-75) years. The main indication was extensive diverticular disease (50%) and previous colonic surgery (21.4%). A defunctioning stoma was performed in 64.3% which was reverved in all within 3 to 6 months. Three (21.4%) patients developed postoperative complications (Clavien-Dindo 1-2) and none required reoperation. The median duration of follow was 11 months. One (7.2%) patients had one bowel movement per day, ten patients (71.4%) had two bowel movements per day and three patients (21.4%) had three per day.Conclusion The modified right colonic inversion technique is safe and achieves intestinal continuity with a tension-free well vascularised anastomosis. Good function and low morbidity show that the procedure is a credible alternative to ileorectal or ileoanal anastomosis.This article is protected by copyright. All rights reserved.
    Colorectal Disease 09/2014; DOI:10.1111/codi.12784 · 2.02 Impact Factor
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    ABSTRACT: A 55 -year-old Asian man was seen in the emergency department with bleeding per rectum. He was a teetotaller and had no previous abdominal surgery. He did, however, report a change in bowel habit towards constipation. He underwent colonoscopy which revealed a lesion, highly suspicious of malignancy, in the caecum. On review by two consultants, a decision to completely resect this lesion was made. Histological analysis of the polypoidal growth showed it to be a consequence of chronic infection with the helminth Enterobius vermicularis. Importantly, there was no evidence of dysplastic or malignant cells. The patient was subsequently discharged with a 3-day course of antihelminthic mebendazole and reassured that his per rectal bleeding was most likely due to haemorrhoids discovered at rectal examination.
    Case Reports 01/2014; 2014. DOI:10.1136/bcr-2013-201599
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    ABSTRACT: Sacral nerve stimulation (SNS) has recently been used in the management of faecal incontinence (FI). This study compared SNS to conservative management with regards to functional and quality of life outcomes. Meta-analysis of studies published between 1995 and 2008 on SNS for FI was performed. Outcomes evaluated were functional, physiological and quality of life. A random-effects model was used and sensitivity analyses performed. Subgroup analyses were performed on age and sphincter status. Thirty-four studies were included, reporting on 944 patients undergoing peripheral nerve evaluation; 665 underwent permanent SNS. Weekly incontinence episodes (weighted mean difference [WMD] -6.83; 95% confidence intervals [CI] -8.05, -5.60; p < 0.001) and incontinence scores (WMD -10.57; 95% CI -11.89, -9.24; p < 0.001) were significantly reduced with SNS; ability to defer defecation (WMD 7.99 min; 95% CI 5.93, 10.05; p < 0.001) was increased. Most SF-36 and FIQL domains improved following SNS, and mean anal pressures increased significantly (p < 0.001). Results remained consistent on sensitivity analysis. The under-56 years age group showed smaller functional but greater physiological and quality of life improvements. Results were similar between sphincter intact and impaired subgroups. The complication rate was 15% for permanent SNS, with 3% resulting in permanent explantation. SNS results in significant improvements in objective and subjective measures for faecally incontinent patients.
    International Journal of Colorectal Disease 03/2011; 26(3):275-94. DOI:10.1007/s00384-010-1119-y · 2.42 Impact Factor
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    ABSTRACT: Known collectively as serrated polyps, hyperplastic polyps (HP), sessile serrated adenomas (SSA/SSP) and traditional serrated adenoma (TSA) may represent a spectrum of increasing malignant potential with characteristic immunological markers. There is increasing evidence that HP, SSA/SSP and TSA are biologically different and are likely to represent a spectrum along the serrated polyp pathway. Although there is general consensus about the diagnostic features of serrated polyps, the morphological differences between the categories are often subtle. This study compares the expression of p53 and P504S among serrated polyps. Sixty seven randomly selected biopsies (n = 59) and resection specimens (n = 8) histologically diagnosed for SSA/SSP, TSA and HP (19, 30 and 18 specimens, respectively) were obtained. There was a significant difference in p53 (P < 0.001) and P504S (P < 0.001) immunopositivity and distribution among the serrated polyps. In particular, there is diffuse expression p53 and P504S in TSA compared to HP and SSA/SSP where p53 and P504S expression was more frequently confined to the lower 1/3 of the crypts. In addition, percentage of cells expressing p53 and p504S expression was higher in TSA than those of HP and SSA/SSP. Immunostains, p53 and P504S, may be useful adjuncts to morphological diagnosis of serrated polyps.
    International Journal of Colorectal Disease 10/2010; 25(10):1193-200. DOI:10.1007/s00384-010-1007-5 · 2.42 Impact Factor
  • The Lancet Oncology 02/2010; 11(2):114-5. DOI:10.1016/S1470-2045(10)70015-2 · 24.73 Impact Factor
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    ABSTRACT: Lateral pelvic lymph-node metastases occur in 10-25% of patients with rectal cancer, and are associated with higher local recurrence and reduced survival rates. A meta-analysis was undertaken to assess the value of extended lateral pelvic lymphadenectomy in the operative management of rectal cancer. We searched Medline, Embase, Ovid, Cochrane Library, and Google Scholar for studies published between 1965 and 2009 that compared extended lymphadenectomy (EL) with standard rectal resection. 20 studies, which included 5502 patients from one randomised, three prospective non-randomised, and 14 retrospective case-control studies published between 1984 and 2009, met our search criteria and were assessed. 2577 patients underwent EL and 2925 underwent non-EL for rectal cancer. Random and fixed-effects meta-analytical models were used where indicated, and between-study heterogeneity was assessed. End-points evaluated included peri-operative outcomes, 5-year survival and recurrence rates. Operating time was significantly longer in the EL group by 76.7 min (95% CI 18.77-134.68; p=0.0096). Intra-operative blood loss was greater in the EL group by 536.5 mL (95% CI 353.7-719.2; p<0.0001). Peri-operative mortality (OR 0.81, 95% CI 0.34-1.93; p=0.63) and morbidity (OR 1.45, 95% CI 0.89-2.35; p=0.13) were similar between the two groups. Data from individual studies showed that male sexual dysfunction and urinary dysfunction (three studies: OR 3.70, 95% CI 1.66-8.23; p=0.0012) were more prevalent in the EL group. There were no significant differences in 5-year survival (hazard ratio [HR] 1.09, 95% CI 0.78-1.50; p=0.62), 5-year disease-free survival (HR 1.23, 95% CI 0.75-2.03, p=0.41), and local (OR 0.83, 95% CI 0.61-1.13; p=0.23) or distant recurrence (OR 0.93, 95% CI 0.72-1.21; p=0.60). Extended lymphadenectomy does not seem to confer a significant overall cancer-specific advantage, but does seem to be associated with increased urinary and sexual dysfunction.
    The Lancet Oncology 09/2009; 10(11):1053-62. DOI:10.1016/S1470-2045(09)70224-4 · 24.73 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate clinical outcomes, quality-adjusted life-years, and the cost-effectiveness gained from percutaneous drainage followed by elective surgery vs. initial surgery for abdominopelvic abscesses related to Crohn's disease. All consecutive patients with spontaneous Crohn's disease-related abdominopelvic abscess from 1997 to 2007 were reviewed. The authors excluded postoperative and perirectal abscesses. Decision analysis during one year of patient life was used to calculate quality-adjusted life-years and the cost-effectiveness of each strategy. Of 94 patients, 48 (51 percent) were initially approached with percutaneous drainage. Thirty-one (65 percent) had successful percutaneous drainage and delayed elective surgery. The factors significantly associated with percutaneous drainage failure were steroid use, colonic phenotype, and multiple or multilocular abscesses. The initial treatment was surgery in the remaining 46 (49 percent) patients. The initial approach with percutaneous drainage gave higher quality-adjusted life-years and was more cost-effective than initial surgery. Percutaneous drainage was the optimal strategy in spite of the risk of failure and septic complications within the plausible range. Percutaneous drainage failure is associated with steroid use, colonic phenotype, and multiple or multilocular abscesses. When feasible, percutaneous drainage is the most effective strategy from the perspective of patients and third-party payers.
    Diseases of the Colon & Rectum 06/2009; 52(5):906-12. DOI:10.1007/DCR.0b013e31819f27c3 · 3.20 Impact Factor
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    ABSTRACT: Fast-track (FT) protocols accelerate patient's recovery and shorten hospital stay as a result of the optimization of the perioperative care they offer. The aim of this review is to examine the latest evidence for fast-track protocols when compared with standard care in elective colorectal surgery involving segmental colonic and/or rectal resection. All randomized controlled trials and controlled clinical trials on FT colorectal surgery were reviewed systematically. The main end points were short-term morbidity, length of primary postoperative hospital stay, length of total postoperative stay, readmission rate, and mortality. Quality assessment and data extraction were performed independently by two observers. Eleven studies were eligible for analysis (four randomized controlled trials (RCTs) and seven controlled clinical trials (CCT)), including 1,021 patients. Primary hospital stay (weighted mean difference -2.35 days, 95% confidence interval (CI) -3.24 to -1.46 days, P < 0.00001) and total hospital stay (weighted mean difference -2.46 days, 95% CI -3.43 to -1.48 days, P < 0.00001) were significantly lower for FT programs. Morbidity was also lower in the FT group. Readmission rates were not significantly different. No increase in mortality was found. FT protocols show high-level evidence on reducing primary and total hospital stay without compromising patients' safety offering lower morbidity and the same readmission rates. Enhanced recovery programs should become a mainstay of elective colorectal surgery.
    International Journal of Colorectal Disease 05/2009; 24(10):1119-31. DOI:10.1007/s00384-009-0703-5 · 2.42 Impact Factor
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    ABSTRACT: The levator ani is the main muscular support of the pelvic floor organs and damage caused by childbirth can affect its function. The full functionality of this muscle group is still unknown but it is essential for effective surgical planning. To elucidate its functional significance, a physical-based statistical shape model was built from the levator ani surfaces of 15 subjects scanned in an open access scanner. Simulation of dynamic exercises was performed on the resulting surfaces with finite element analysis. Statistical shape modeling was performed on the training set consisting of the original and simulated shapes along with thickness and strain distributions. Simulation results are presented on 15 subjects. The statistical shape model shows good correspondence to inter- and intra-subject shape variability, with the modes of variation highlighting movement in the posterior of the levator ani as well as in the levator arms. Strain distribution plots and the modes of variation show results that correspond to clinical findings. Further validation of the technique and a repeatability test were performed on four subjects with internal global pressure readings taken from a perineometer and five patients suffering from minor pelvic floor disorders due to obstructed defaecation. A Mann-Whitney nonparametric test was used to compare the normal model fitting to the two subject groups.
    02/2009; 28(6):926-36. DOI:10.1109/TMI.2009.2012894
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    ABSTRACT: Narrow band imaging is a new endoscopic technology that highlights mucosal surface structures and microcapillaries, which may be indicative of neoplastic change. To assess the diagnostic precision of narrow band imaging for the diagnosis of epithelial neoplasia compared to conventional histology both overall and in specific organs. We performed a meta-analysis of studies which compared narow band imaging-based diagnosis of neoplasia with histopathology as the gold standard. Search terms: 'endoscopy' and 'narrow band imaging'. Five hundred and eighty-two patients and 1108 lesions in 11 studies were included. Overall, sensitivity was 0.94 (95% confidence interval 0.92-0.95), specificity 0.83 (0.80-0.86); weighted area under the curve was 0.96 (standard error 0.02), diagnostic odds ratio (DOR) 72.74 (34.11-155.15). DORs were 66.65 (25.84-171.90), 61.19 (7.09-527.97), 69.74 (8.04-605.24) for colon, oesophagus and lung respectively. Studies with more than 50 patients had higher diagnostic precision, relative DOR 4.96 (1.28-19.27), P = 0.022. There was no difference in accuracy between microvessel and mucosal (pit) pattern based measures, relative DOR 1.29 (0.05-35.16), P = 0.87. There was significant heterogeneity overall between studies, Q = 31.2, P = 0.003. Narrow band imaging is accurate with high diagnostic precision for in vivo diagnosis of neoplasia across a range of organs, using simple microvessel-based measures.
    Alimentary Pharmacology & Therapeutics 10/2008; 28(7):854-67. DOI:10.1111/j.1365-2036.2008.03802.x · 4.55 Impact Factor
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    ABSTRACT: Several environmental and genetic factors have been implicated to date in the development of Crohn's disease (CD) and ulcerative colitis (UC). The aim of this study was to provide a quantification of the risk of oral contraceptive pill (OCP) use in the etiology of inflammatory bowel disease. A literature search was performed to identify comparative studies reporting on the association of oral contraceptive use in the etiology of UC and CD between 1983 and 2007. A random-effect meta-analysis was used to compare the incidence of UC or CD between the patients exposed to the OCP and nonexposed patients. The results were adjusted for smoking. A total of 75,815 patients were reported on by 14 studies, with 36,797 exposed to OCP and 39,018 nonexposed women. The pooled relative risk (RR) for CD for women currently taking the OCP was 1.51 (95% confidence interval [CI] 1.17-1.96, P= 0.002), and 1.46 (95% CI 1.26-1.70, P < 0.001), adjusted for smoking. The RR for UC in women currently taking the OCP was 1.53 (95% CI 1.21-1.94, P= 0.001), and 1.28 (95% CI 1.06-1.54, P= 0.011), adjusted for smoking. The RR for CD increased with the length of exposure to OCP. Moreover, although the RR did not reduce once the OCP was stopped, it was no longer significant once the OCP was stopped (CI contains 1), both for CD and for UC. This study provides evidence of an association between the use of oral contraceptive agents and development of IBD, in particular CD. The study also suggests that the risk for patients who stop using the OCP reverts to that of the nonexposed population.
    The American Journal of Gastroenterology 09/2008; 103(9):2394-400. DOI:10.1111/j.1572-0241.2008.02064.x · 9.21 Impact Factor
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    ABSTRACT: Artificial bowel sphincter (ABS) and dynamic graciloplasty (DG) are surgical treatments for faecal incontinence (FI). FI may affect quality of life (QOL) so severely that patients are often willing to consider a permanent end stoma (ES). It is unclear which is the more cost-effective strategy. Probability estimates for patients with FI were obtained from published data (ABS, n = 319; DG, n = 301), supplemented by expert opinion. The primary outcome was quality-adjusted life years (QALYs) gained from each strategy. Factors considered were the risk of failure of the primary and redo operation and the consequent risk of permanent stoma. Results were assessed as incremental cost-effectiveness ratio (ICER). Over the 5-year time horizon, ES gave a QALY gain of 3.45 for 16,280 pounds sterling, giving an ICER of 4719 pounds sterling/QALY. ABS produced a gain of 4.38 QALYs for 23,569 pounds sterling, giving an ICER of 5387 pounds sterling/QALY. DG produced a gain of 4.00 QALYs for 25,035 pounds sterling, giving an ICER of 6257 pounds sterling/QALY. With the willingness-to-pay threshold set at 30,000 pounds sterling/QALY, ES was the most cost-effective intervention. The ABS was most cost-effective after 10 years. All three procedures were found to be cost-effective. The ES was most cost-effective over 5 years, while the ABS was most cost-effective in excess of 10. DG maybe considered as an alternative in specialist centres.
    Colorectal Disease 08/2008; 10(6):577-86. DOI:10.1111/j.1463-1318.2007.01418.x · 2.02 Impact Factor
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    ABSTRACT: The aim of the study was to evaluate the diagnostic precision of serum carcinoembryonic antigen (CEA) in the detection of local or distant recurrence following resectional surgery for colon and rectal cancer. Quantitative meta-analysis was performed on 20 studies, comparing serum CEA with radiological imaging and/or pathology in detecting colorectal cancer (CRC) recurrence in 4285 patients. The cut-off for a 'positive' CEA ranged from 3 to 15 ng/ml between the various studies. Sensitivity, specificity and diagnostic odds ratio (DOR) were calculated for each study. Summary receiver operating characteristic curves (SROC) and sub-group analysis were undertaken. The overall sensitivity and specificity of CEA for detecting CRC recurrence was 0.64 (95% CI: 0.61-0.67) and 0.90 (95% CI: 0.89-0.91), respectively. The area under the SROC curve was 0.75 (SE=0.04) and the diagnostic odds ratio was 18.44 (95% CI: 11.94-28.49). A CEA cut-off of 5 ng/ml yielded a higher diagnostic odds ratio than a cut-off of 3 ng/ml (15.5 vs. 11.1). Using meta-regression analysis the optimum CEA cut-off point for the best combination of sensitivity and specificity was 2.2 ng/ml. On sub-group analysis high quality studies, and those involving > or =100 patients yielded a marginal improvement in the sensitivity and specificity with minimal change to the SROC. Serum CEA is a test with high specificity but insufficient sensitivity for detecting CRC recurrence in isolation. A cut-off of 2.2 ng/ml may provide an ideal balance of sensitivity and specificity. It may be useful as a first-line surveillance investigation in patients during surgical follow-up based on serial CEA measurements using temporal trends in conjunction with clinical, radiological and/or histological confirmation.
    Surgical Oncology 07/2008; 18(1):15-24. DOI:10.1016/j.suronc.2008.05.008 · 2.37 Impact Factor
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    ABSTRACT: This study aims to evaluate the diagnostic precision of endoanal magnetic resonance imaging in identifying anal sphincter injury and/or atrophy when compared with either endoanal ultrasound or surgical diagnosis. Quantitative meta-analysis was performed on nine studies, comparing endoanal MRI with endoanal ultrasound or surgical diagnosis in 157 patients. Sensitivity, specificity, and diagnostic odds ratio were calculated for each study. Summary receiver operating characteristic curves (SROC) and subgroup analysis were undertaken. The overall sensitivity and specificity of endoanal MRI for external sphincter injury was 0.78 (95%CI: 0.66-0.84) and 0.66 (95%CI: 0.51-0.79), respectively. For internal sphincter injury detection, this was 0.63 (95%CI: 0.50-0.74) and 0.71 (95%CI: 0.60-0.81), respectively. For detection of atrophy, this was 0.86 (95%CI: 0.71-0.95) and 0.82 (95%CI: 0.65-0.93), respectively. The area under the SROC curve and diagnostic odds ratio were 0.84 (SE = 0.07) and 6.14 (95%CI: 2.17-17.4) for external sphincter injury, 0.79 (SE = 0.07) and 4.60 (95%CI: 1.75-12.15) for internal sphincter injury, and 0.92 (SE = 0.08) and 21.49 (95%CI: 2.87-160.64) for sphincter atrophy. Endoanal MRI was sensitive and specific for the detection of external sphincter injury and especially sphincter atrophy. It may be useful as an alternative to endoanal ultrasound in patients presenting with fecal incontinence, although further clinical studies are needed to identify its best application in clinical practice.
    International Journal of Colorectal Disease 07/2008; 23(6):641-51. DOI:10.1007/s00384-008-0449-5 · 2.42 Impact Factor
  • Gastroenterology 04/2008; 134(4). DOI:10.1016/S0016-5085(08)62094-6 · 13.93 Impact Factor
  • Gastroenterology 04/2008; 134(4). DOI:10.1016/S0016-5085(08)62978-9 · 13.93 Impact Factor
  • Gastroenterology 04/2008; 134(4). DOI:10.1016/S0016-5085(08)60231-0 · 13.93 Impact Factor

Publication Stats

584 Citations
180.42 Total Impact Points


  • 2007–2015
    • Imperial College London
      • Section of Biosurgery and Surgical Technology
      Londinium, England, United Kingdom
  • 2010–2014
    • The Royal Marsden NHS Foundation Trust
      Londinium, England, United Kingdom
  • 2007–2014
    • Imperial Valley College
      Westminster, Colorado, United States
  • 2008
    • St. Mark's Hospital
      Harrow, England, United Kingdom